Formation-testing apparatus



Jan. 3, 1967 E. F. BRIEGER ETAL. 3,295,615

FORMATION-TESTING APPARATUS original Filed oct. 31, 1965 7 sheets-sheet 1 INVENTORS,

EMMET F. BRIEGER a ULRICH EAVOETTER their ATTORNEYS RECORDER Jan. 3, 1967 E. F. BRIEGER ETAL 3,295,515

FORMATION-TESTING APPARATUS Original Filed Oct. 3l, 1963 '7 Sheets-Sheet fheif ATTR/VEYS Jan 3 1967 E. F. Bmx-:GER ETAL 3,295,615

FORMATION- TESTING APPARATUS F. BRIEGER ETAL.

FORMATION-TESTING APPARATUS Original Filed OCb. 5l, 1963 Jan. 3, 1967 7 Sheets-Sheet 4 Am. a m,

`INVENTORS- ET E BRIEGER 8| CH E. VOETTER nmwmu m En, m. mmv i m EMM BY ULRI M FM, W 2

their ATTORNEYS Jan. 3, 1967 E. F. BRIEGER ETAL 3,295,65

FORMATION-TESTING APPARATUS original Filed oct. s1, 1963 E 7 sheets-sheet s INVENTORS. E ET E B GER Bx U CH E. V TER BY their ATTORNEYS Jan. 3, 1967 E. F. BRIEGER ETAL 3,295,615

FORMATION-TESTING APPARATUS Original Filed Oct. 3l, 1963 7 Sheets-Sheet 5 n@u` 2231 25"m 22/ i 226 i 5,0 F/G' 9 65 f5@ l 2?; 65@

INVENTORS. EM T E BRIEGER ul. H E. voETTER their ATTORNEYS E, QM Mw@ Jan. 3, 1967 E. F. BRIEGER y ETAL 3,295,515

FORMATION-TESTING APPARATUS Original Filed Oct. 3l, 1963 7 Sheets-Sheet 'R INVENTORS. EMMET E BRIEGER 8 ULRICH E. VOETTER BY MJ FM WMM/L their ATTORNEYS United States Patent() 3,295,615 FORMATION-TESTING APPARATUS Emmet F. Brieger, Needville, and Ulrich E. Voetter,

Houston, Tex., assignors to Schlumberger Well Surveying Corporation, Houston, Tex., a corporation of Texas Continuation of application Ser. No. 320,410, Oct. 31, 1963. This application Oct. 22, 1965, Ser. No. 506,444 27 Claims. (Cl. 175-4.52)

This application is a continuation of our copending application Serial No. 320,410, filed October 31, 1963, now abandoned, for Formation Testing Apparatus.

This invention relates to new and improved formation testing apparatus and methods and, more particularly, to test apparatus and methods directed to the acquisition of a tluid sample from earth formations traversed by a bore.

Heretofore, one type of formation testing apparatus, for use in medium-to-hard (consolidated) formations, has employed a single packotf shoe with a sealing mem` ber which is driven into engagement with the sidewall of a borehole, the sealing member having a relatively large borehole wall-engaging surface designed to isolate a portion of the formation from the usual drilling fluid in the borehole. Perforating means in the apparatus opens the isolated portion of the formation to permit uids from the formation to flow via the perforator port to a sample receiving chamber. After a desired amount of fluid is obtained, the sample receiving chamber is closed, the shoe and sealing member retracted, and the apparatus withdrawn from the borehole so that the sam ple may be measured and analyzed. Apparatus of this type is more completely described in Patents Nos. 3,011,- 554 and 2,674,313.

For use in a very soft or unconsolidated formation, a formation tester apparatus is used wherein a snorkel or fluid sampling tube is forced into the formations through a sealing member so that the fluid sample flows through the tube to the sample receiving chamber, the tube minimizing the effect of formation erosion. Apparatus of this type is more completely described in Patent No. 2,965,176.

Another type of formation testing apparatus is disclosed in a patent to Frank 1R. Whitten, No. 3,104,712. This type of testing apparatus has longitudinally spaced sealing members for sampling an interval of earth formations and is useful in medium-to-hard formations or cased holes. In this apparatus, shaped charges produce spaced perforations from which fluid flow is deposited in a sample receiving chamber.

Where the character (e.g., consolidation, permeability, etc.) of the formations to be sampled is known, there is no particular problem in selecting `a particular type of testing apparatus to perform a test. If, however, the character of the formations is unknown or in doubt, whether or not a sample is obtained is dependent upon a chance selection by the operator. That is, if the formations are soft, a snorkel tester may work where testers using shaped charges fail to seal and, conversely, where the formations are hard, a tester using shaped charges may work where a snorkel tester would fail to get a sample from the formations.

In accordance with all of the various apparatus and methods referred to above, it is necessary to form a fluid seal about the portion of the bore wall from which a fluid sample is to be taken to establish communication between such portion and the sample receiving apparatus while isolating such por-tion from the bore uid. Conventional apparatus for performing this function is unsatisfactory in that the great differential pressure generally obtaining between the high pressure fluidin the bore and the relatively low pressure fluid, if any, drawn from the wall of the bore tends to extrude the packer or other resilient sealing means into the low pressure region, which results in destruction of the packer. This effect is particularly pronounced in uncased bores whose walls are very soft or have a tendency to crumble or are very irregular. In such cases, there may immediately, or after a period of time, result a condition in which the surface of the resilient sealing means intended to form a seal with the bore Wall, or at least a portion of such surface, is spaced apart from the bore wall. The packer is then unable to withstand the force of extrusion exerted by the fluid in the bore.

Accordingly, it is an object of the present invention to provide new and improved resilient sealing means for use in fluid testing apparatus for reliably obtaining a fluid sample from earth formations independently of their consolidation and permeability characteristics.

In accordance with the invention, resilient sealing means, preferably annular, is provided for establishing a fluid seal between a high pressure region and a low pressure region, and rigid means are provided connected to the resilient sealing means for preventing extrusion of the resilient sealing means into the low pressure region. Second rigid means may be connected to the resilient annular sealing means, and means may be provided for facilitating movement of the rst rigid mean with respect to the second rigid means, the direction of the movement preferably being along the axis of the resilient `annular sealing means, so that a portion of the resilient annular sealing means is adapted to follow a crumbling wall and maintain good sealing relation therewith irrespective of such crumbling.

The novel sealing means is particularly adapted for use on fluid testing apparatus of the type disclosed in an application Serial No. 184,826, now abandone-d, by Frank R. Whitten and the Whitten continuation applications Serial No. 384,024, now abandoned, and Serial No. 492,- 975, now issued as U.S. Patent No. 3,261,402. Such apparatus is provide-d with longitudinally spaced sample admitting means on a well tool movable into sealing engagement with the wall of a well bore. While sealing engagement with the well bore is maintained, a test probe or sampling tube is arranged to `be forced into the formations through one of the sample admitting means and opened to the sample receiving chamber in the tool body. If .the formations are soft and permeable, a Huid sample is recovered; if they are hard and permeable, a fluid sample -rnay or may not .be recovered depending upon the degree of permeability and presence of mud cake or other plug in the formations. If, however, the formations have low permeability or are blocked near the surface of the bore, as is possible on hard formations, there is no iluid flow. The occurrence of fluid ow is monitored by pressure measurements indicated at the earths surface. If no flow occurs, the sampling tube is plugged, the formations have low permeability, or the formations are effectively blocked to prevent fluid ow.

The other sample admitting means is then opened by a shaped charge which produce a penetration of the earth formation and couples the sample admitting means to the sample receiving chamber in the tool. If the pressure measurements indicate a uid flow, then the formation is permeable and the sampling tube is plugged. If there is no fluid flow, the formation is assumed to have a low permeability. t

The novel features of the present invention are set forth in the appended claims. The present invention, both as to its organization and manner of operation together with further objects and advantages thereof, may best be understood by way of illustration and example when taken in conjunction with the accompanying drawings, in which:

FIG. 1 is a diagrammatic view in elevation of a fluid sampling apparatus embodying the present invention and shown disposed in a borehole;

FIG. 2 is a diagrammatic illustration of the operation portions of lthe fluid sampling apparatus, which are arranged for lowering in a well;

FIGS. 3-10 are detailed horizontal sections of apparatus constructed in accordance with the invention; and

FIG. 11 is a detailed horizontal section of apparatus constructed in accordance with the invention showing -the manner in which it is adapted to maintain a seal with the wall of a bore irrespective of crumbling of the wall.

In FIG. 1 of the drawings, a formation testing apparatus is shown disposed in a bore 11 traversing earth formations 12, 13, 14,-where the formation 13 is the one of interest from which a fluid sample is to be obtained. The bore 11 contains a fluid 15 to provide a hydrostatic control pressure for the well in a conventional manner. The apparatus 10 is suspended in the bore 11 by a cable 19 connected to a winch 2t) located at the surface of the earth, the winch and cable serving to lower and raise the apparatus in a customary manner.

The formation testing apparatus 10 generally comprises upper and lower pressure resistant housing sections 16 and 17 connected together in longitudinally spaced relation by a testing section 18. The upper section 16 generally contains hydraulic motive means for the testing section while lower section 17 generally contains the sample receiving means. The testing section l18 is provided with spaced uid sample admitting means 21, 22 embodying the present invention and extending outwardly from the section 18 and disposed along the length of the section 18 so as to lie in a central plane extending longitudinally of the testing section 18. Diametrically opposite the sample admitting means 21, 22 is a wall-engaging .member 23 mounted so as to move between a retracted position and an extendedy position.

In the extended position of the wall-engaging member 23 shown, the fluid sampling means 21, 22 are in sealing engagement with the wall of the bore 11. In this posi- .'tion, a sampling tube 60 (FIG. 2) in the sampling means 22 is urged into the earth formation 13 and the occurrence or non-occurrence of fluid flow noted from surface indicated pressure measurements (FIG. 1). If ow occurs, the sample is 'obtained in a manner described hereinafter and the tool yretrieved from the well bore 11. If, however, no ow occurs, perforating means such as a shaped charge 59 (FIG. 2) associated with the sample admitting means 21 is employed to perforate the formation 13 thereby providing any iiuid present in the earth formation 13 access to the testing section 18, if the formation 13 is permeable.

FIG. 2 diagrammatically illustrates the operational components of the apparatus 1t) to show more clearly their overall relationship and operation.

In the rst step of operation, the sample admitting means 21, 22 are placed in sealing engagement with the wall of the bore 11. To attain the sealing engagement, the wall-engaging member or backup shoe 23 is moved relatively to the testing section 18 by a hydraulic system which includes a hydraulic pressure means 30 (FIG. 2) connected through a pressure regulating valve 31 to a high pressure conduit 32, the conduit 32 opening into a cylinder 33 in the testing section 18. A piston 34 is slidably and sealingly received in the cylinder 33 and has an end portion secured to the wall-engaging member 23 so that, when the pressure -means 30 is actuated, the piston 34 travels outwardly from the testing section 18 by virtue of hydraulic pressure applied to the Huid medium in the hydraulic system. The wall-engaging member 23, upon engaging the wall of the Ibore 11, permits the pres- `sure on the piston 34 to urge the sampling means 21, 22

into sealing engagement with the wall of the bore 11 on the side thereof opposite the member 23.

The conduit 32 at its lower end is blocked by a normally closed break valve 36 which, when open, couples the high pressure conduit 32 through another conduit 37 to a seal valve 38. This function is for sealing in the collected sample and is more fully explained in the description to follow in the proper sequence of operation.

It is, of course, also necessary to provide for reduction of the hydraulic pressure when it is desired to retract the wall-engaging member 23 and this is more fully explained in the description to follow, it being suflicient to note here that the upper end portion of the conduit 32 has an extension 39 leading to a normally closed break valve 40, the valve 40 blocking the conduit 32 from a dump chamber 41.

To provide indications of the pressure of the hydraulic system, a pressure transducer 42 is connected by a conduit extension 43 to the conduit 32. The transducer 42 is adapted to produce electrical signals in response to pressure changes, and a conductor 42a connected to the transducer 42 passes through the cable 19 (FIG. 1) to conventional indicating means 44 and a conventional recorder 45 which provide indications of the pressure of the hydraulic system.

Of the foregoing portions of the described apparatus, the pressure means 30, regulating valve 31, dump chamber 41, break valve 40, and transducer 42 are located in the upper housing 16 (FIG. l) of the apparatus 10. The pressure means 30 (FIG. 2) includes upper and lower cylinders 46, 47 of different diameters'which, respectively, slidably and sealingly receive upper and lower pistons 48, 49, the pistons being interconnected by a longitudinally extending rigid member 50. The upper cylinder 46 is connected to a normally closed break valve 51 which has an opening 52 to the exterior of the housing section 16 (FIG. 1) so that, when the valve 51 is actuated, bore fluid may enter the upper end portion of the cylinder 46 via the valve means 51. The valve 51, which is subsequently more fully explained, is adapted to .be actuated-by electrical energy 'supplied via a conductor 51a which passes through the cable 19 to surface control equipment 53 (FIG. 1). Thus, when the bore fluid 15 under hydrostatic pressure enters the cylinder 46, the piston 48 moves downwardly so that the interconnected piston 49 in the cylinder 47 also moves downwardly thereby compressing the fluid in the hydraulic system. Because of the smaller diameter of piston 49 and cylinder 47, the pressure means 30 acts as a pressure multiplier, increasing the pressure in the cylinder 47 to a greater value than the hydrostatic pressure in the bore 11 at the level of the apparatus 10. The regulator valve 31 in the conduit 32 limits the pressure in the conduit 32 to a predetermined value regardless of the hydrostatic pressure in the well, thereby preventing pressure in excess of the pressure rating of the system.

In the testing section 18 (FIG. 1) are the sampling means 21, 22 (FIG. 2) which include resilient annular sealing means 55, 56 constructed in accordance with the invention and disclosed in greater detail hereinafter.

The sampling means 21 includes shaped charge explosive means 59 disposed in a chamber 59', the chamber 59 being closed by a thin walled closure 58. In the sealing means 55 is a thin walled closure 57 spaced from the closure 58, the closures 57 and 58 defining therebetween a passageway 65. The closure 57 provides a flow blocking device for the passageway 65', normally closing the sealing means 5S from fluid flow therethrough. The closures 57 and 58 may be thin walled cap members received in a threaded bore.

The shaped charge 59 is connected to igniter means such as a primacord 61 and a blasting cap 62, the blasting cap being ignitable upon receipt of electrical energy from the control equipment 53 (FIG. l) via a conductor 62a (FIG. 2) in the cable 19 (FIG. l). Hence,

when the sealing means 55, 56 are in sealing engagement with the wall of the bore 11 and the shaped charge 59 (FIG. 2) is detonated, a perforation is produced in the adjacent earth formation thereby permitting formation fluids, if present, to flow through the perforated wall portion of the closure 57 into the passageway 65.

The sampling means 22 includes a thin walled tube, tube follower, or tube member 60 mounted centrally of the sealing means S6 for transverse movement into earth formations. The tube 60 is preferably constructed of a frangible, non-porous material and has, at its rearward end, a piston portion 63 slidably and sealingly received in a cylinder 64. A passageway 71 couples the end of the cylinder 64 to the high pressure conduit 32 and has a llow choke 72 therein. When the pressure in the conduit 32 is increased to place the sampling means 21, 22 in sealing engagement with the well bore 11, the choke 72 delays operation of the tube 60 and piston 63 until after the sampling means 21, 22 are sealed to the bore wall by the action of the piston 34. Then the pressure in the conduit 32 is applied to the piston 63 to urge the forward end of the t-ube 60 into the earth formation. The tube 60 has a rearward opening 74 placing its interior in lluid communication with the cylinder 64.

The tube 60 slides through a seal formed about the forward end thereof. The cylinder 64 communicates with the passages or conduits 65, 66.

The cylinder 64 is connected for fluid communication to the sample admitting means 21 by the conduit 65. The cylinder 64 is also connected by the conduit 66 to a normally closed break valve 67. The valve 67 is provided with an electrical conductor 67a extending through the cable 19 (FIG. l) to the surface control means 53. Also 4connected to the` conduit 66 (FIG. 2) between the cylinder 64 and valve 67 is a pressure transducer 68 which corresponds in construction to the transducer 42 and derives indications of the pressure in the conduit 66 which, in turn, provide pressure information about the fluids in the earth formations. The transducer 68 is similarly connected by a conductor 68a to indicating means 69 (FIG. 1) at the surface of the earth and also to the recorder 4S. Thus, when the valve 67 is opened to permit fluid ilow, such flow, if it occurs, is at a pressure dependent upon the pressure of the lluids in the formation, and the pressure is sensed by the pressure transducer 68 and recorded by the surface indicating equipment.

The valve 67, when opened, connects the conduit 66 via a conduit 70 to the seal valve 38. The seal valve 38 Opens into a sample receiving device 73. Hence, when the valve 67 is opened, formation fluids may flow via the conduit 70 and seal valve 38 to the sample receiving device 73. Of course, the pressure of the flowing sample fluids may lbe continuously sensed by the pressure transducer 68 and recorded.

The seal valve 38 generally includes upper and lower cylinders 85, 86 which are adapted, respectively, to receive an upper sealed piston 87 and a lower sealed valve head 88, the piston 87 and head 88 being interconnected by a. rigid `member 89. In the normal position of the seal valve 38, the piston 87 is in an upward position in the cylinder 85 so that the valve head 88 does not block the cylinder 86 and a fluid sample is permitted to llow through the conduit 70 to the sample receiving device 73. To operate the seal valve 38 to close the sample receiving device 73, the upper end of the cylinder 85 is connected by the conduit 37 to the normally closed valve 36 in the high pressure conduit 32. The valve 36 has a conductor 36a extending through the cable 19 (FIG. l) to the surface control means S3. Thus, when the valve 36 (FIG. 2) is opened, high pressure is applied to the piston 87, moving it downward so that the piston 88 enters the cylinder 86 and is locked in place by locking means (not shown) to seal olf the opening to the sample receiving device 73 thereby preventing further fluid llow into or out of the device 73.

The sample receiving device 73 generally includes upper and lower chambers 91, 92 separated by a partition 93 having a flow-restricting orice 94. A fluid 95, such as water, is disposed in the upper chamber 91 and separated from the cylinder 86 by a floating piston 96 which is initially positioned in the upper end of the chamber 91. The lower chamber 92 is filled with air, the piston 96 being held in position by frictional forces of piston sealing means, such as O rings. Hence, formation fluids entering the cylinder 86 move the piston 96 downwardly at a rate determined by the ilow of fluid through the orifice 94.

To retrieve the apparatus 10 after a sample has been obtained, it is necessary merely to disengage the wall-engaging member 23 and sealing means 55, 56 from the bore. The dump valve 40 is provided with a conductor 40a extending through the cable 19 (FIG. l) to the surface control means 53, and, when the dump valve 40 (FIG. 2) is actuated by the surface control means 53 (FIG. l), the fluid in the hydraulic system is permitted to ilow into the dump chamber 41 (FIG. 2).. The chamber 41 has a volume sufficient to receive the hyd-raulic fluid of the pressure system and is at atmospheric pressure thereby to reduce to a small value the pressure on the fluid in the system. The dump chamber 41 includes a rst chamber and a second chamber 101 which are interconnected by a tlow-restricting orifice 102. The first chamber 100 is connected by a conduit 103 to the rearward end of a cylinder 104 of a pressure-equalizing valve 105. A piston 106 is slidably and sealingly received in the cylinder 104 and spaced from an end wall of the cylinder by an extension 106. Another piston 108 of smaller diameter is slidably and sealingly received in a bore 109 and has an extension 107 in abutment with the piston 106. The bore 109 extends between the cylinder 104 and the exterior of the testing section 18 (FIG. l) so that the bore fluid 1S acts upon the piston 108 (FIG. 2) to urge it inwardly toward cylinder 104, the piston 108 preventing bore fluid from entering the bore 109.

A channel 110 extends between the bore 109 and the passageway 65' of the sampling means 21. When the dump valve 40 is opened, the orifice 102 momentarily restricts the relief of the pressure and permits a surge of pressure to be applied to the piston 106 to move it to the left so that the piston 108 is moved out of the bore 109. The extension 107 of the piston 108 is of lesser diameter than the piston 108 and permits the bore fluid to flow into the channel 110. In the just described position, means (not shown) are provided to retain the piston 108 in its open position. Thus, in the open position of the piston 108, bore fluid 15 (FIG. 1) is permitted to enter the cylinder 109 (FIG. 2) and pass through channel 110 to the passageway 65 and the cylinder 64 of the sample receiving means 21, 22, and the pressure across the sealing means 5S, 56 (if both are open) is equalized to facilitate removal of the sealing means from the wall of the bore 11. Also, the hydrostatic mud pressure acts on the piston 63 in the cylinder 64 to retract it.

When the hydraulic pressure in the conduit 32 is reduced by iluid flow into dump chamber 41, the pressure of the well lluid on the piston 34 becomes greater than the pressure of the hydraulic system on the piston 34, and the resulting movement of the piston 34 urges the wall-engaging member 23 toward a retracted position. To facilitate the retraction of the member 23, should it stick to the wall of the bore, heavy springs 112, 113 are connected between the member 23 and the testing section 18 (FIG. 1), the springs 112, 113 (FIG. 2) being tensioned in the extended position of the member 23 so that the force of the springs 112, 113 tends to move the member 23 inwardly toward a retracted position.

The surface control apparatus S3 (FIG. l) includes a movable contact arm 11.5 for a multicontact switch 116, the contacts of which are connected, in counterclockwise fashion, to the conductors 51a, 62a, 67a, 36a, and 40a, which correspond to the conductors in the apparatus 10 as previously described. The contact arm 115 is connected to a source of electrical energy 117 whereby the various electrical circuits in the apparatus may bey supplied with electrical power.

In operation, the apparatus 10 (FIG. 1) is lowered in the bore 11 to the level to be tested by means of the cable 19 and winch 20. The movable arm contact 115 is then moved clockwise to supply electrical energy via the conductor 51a to actuate the valve 51 (FIG. 2) in the housing section 16 (FIG. 1). Thus, the valve 51 (FIG. 2) opens and permits the bore fluid (FIG. 1) to actuate the pressure means 30 (FIG. 2) and produce amplified hydraulic pressure for the hydraulic system. The pressure of the fluid in the hydraulic system is regulated by the regulating valve 31 and applied via the conduit 32 to the cylinder 33 containing the piston 34 which moves the wall-engaging member 23 relatively to the testing section 18 (FIG. 1) until the sealing means 55, 56 (FIG. 2) of the fluid sampling means 21, 22 sealingly engage the wall of the bore 11. The dump valve 40 and valve 36 associated with the conduit 32 are, of course, normally closed.

As the sealing means 55, 56 of the fluid sampling means 21, 22 move into sealing engagement with the wall of the bore 11 (FIG. 1), the pressure in the hydraulic system increases to the maximum value of the hydraulic system thereby further compressing the sealing means 55, 56 (FIG. 2). The pressure of the hydraulic system is sensed by the pressure responsive means 42 and recorded. As soon as the sealing means 55, 56 are sealed on the bore wall, the pressure applied via the passageway 71 to the piston 63 urges the tube 6) into the formation.

At this time, if the formation 13 (FIG. 1) is permeable and fluid flows, the pressure of the formation uids is built up in the testing section 18 and is sensed by the pressure responsive means 68 (FIG. 2) to provide an indication of the initial pressure characteristic of the formation fluids over a period of time.

Next, the conductor 67a is connected to the source of electrical energy 117 to open the valve 67 thereby permitting the fluid to flow Yinto the sample receiving device 73 via the conduit 70 and seal valve 38. As the sample chamber 91 receives the formation uids, the floating piston 96 is moved downwardly thereby displacing the cushioning fluid 95 below it through the orifice 94 into the lower `chamber 92.

After a suitable time has elapsed to obtain the fluid sample, the source of electrical energy 117 is connected to the conductor 36a to open the valve 36. The valve 36 couples the pressure of the hydraulic system to the seal valve 38 so that the piston 87 of the seal valve means is actuated, moving the piston 88 into the bore 86 and closing the sample receiving chamlber 73. If the sample chamber 73 fills up, a nal pressure reading is obtained before closing the seal valve. If, however, the chamber 91 does not lill up in a certain length of time, the closing of the seal valve 38 permits a nal pressure reading of the formation to be obtained by the transducer 68.

Thereafter, the source of electrical energy 117 is connected to the conductor 40a, and the dump valveI 40 is actuated to reduce the hydraulic pressure of the system. The orifice 102 retards the reduction of pressure so that a surge of hydraulic pressure is applied to the pressure equalizing valve 105 via the conduit 103 to move the pistons 106 and 108 to the left, unblock the bore 109, and permit bore Huid 15 (FIG. 1) to enter the conduits 110 (FIG. 2), 65, and 66. Thus, actuation of the dump valve 40 permits the pressures across the sealing means 55, 56 to be equalized. At the same time, the hydrostatic pressure acts on the piston 63 to retract it from the earth formation 13. The pressure of the bore fluid 15 (FIG. 1) is also sensed by the pressure responsive means 68 (FIG. 2).

As the pressure of the hydraulic system decreases, the pressure of the bo-re uid 15 urges the member 23 towards a retracted position, this movement being assisted by the springs 112, 113, which are tensioned in the extended position of the member 23. When the member 23 is completely retracted, the apparatus 10 (FIG. 1) is retrieved from the bore and the sample collected in the upper chamber 91 lof the sample receiving device 73 analyzed.

Should the tube 60 fail to retract, its frangible construction permits breaking thereof so the apparatus 10 is not stuck in the well bore 11.

If there is no uid flow, the fact is indicated by the response of the pressure responsive means 68. Then the conductor 62a is connected to the source of electrical energy 117 to detonate the shaped charge device 59. The perforatin-g jet from the shaped charge 59 opens closure members 58, 57 and -penetnates the earth formation 13 to place the sample admitting means 21 in uid communication (via the passageways 65', 65, 66, 70) with the sample receiving chamber 73. If the formations are hard but permeable, the perforation permits fluid flow. If the formations have low permeability, no fluid flows. Fluid ow, if it occurs, is to the sample -receiving device 73; the fluid sample is obtained and the tool is retracted and retrieved as described heretofore.

Much of the structure disclosed in the preced-ing par-t of the specification is disclosed in the aforesaid U.S. patent to Frank R. Whitten No. 3,104,712 and said patent application and does not, per se, constitute the present invention. The present invention is directed to a novel `sealing means and method and to the novel cooperation of the sealing means with the apparatus described hereinabove.

FIGS. 3-11 illustrate in detail the novel sealing means and structure associated therewith. Certain passages and other structure, such as the passage 65, shown d-iagrammatically in FIG. 2 -are shown in `a preferred physical form in one or more of FIGS. 3-11 and are identified by reference numerals identical to those used in FIG. 2. The use of the refer-ence numeral 65a again, for example, in yassociation with a tube follower instead of a shaped charge follower indicates that the positions of the sample admitting means 21, 22 shown in FIG. 2 may be reversed. Also, the identification of parts of FIGS. 3-11 by reference numerals other than those applied to corresponding parts of FIG. 2 indicates that lthe embodiments of the invention illustrated in FIGS. 3-11 may tbe used in cornbination with apparatus other than that shown by way of example in FIG. 2.

FIG. 3 illustrates in detail a representative embodiment of resilient sealing means 118 constructed in accordance with the invention. The sealing means 118 is preferably annular :and establishes a uid seal between `a high pressure region [the locus of the uid 15 (FIG. 1) in the bore 11 to one side of `the reslient sealing means 118] and a low pressure region [the locus of the iiuids, if any, in an earth formation isolated or sealed off by the sealing means 118 with access to the sample admitting means 21 or 22 (FIG. 1) or the region in the vicinity of the axis of the resilient annular sealing means 118 sealed olf by the lresilient annular sealing means 118 from the uid 15 (FIG. 1) in the bore- 11]. The fluid seal is obtained by compression of the resilient sealing means 118 against the borehole wall.

Referring now to FIG. 3, the sealing means 118 is preferably annular, thus having an outer peripheral surface 120, `an inner bore 123, a seal forming surface 124 curved to complement the shape of a borehole wall, and a rearward flat surface 12041. Bore 123 has an outer section 125 of increased diameter and an inner section or recess 136 of increased diameter. A tubular nose piece or central insert member 119 is received within bore 123 Iand `is complementarily shaped at 127 and 127a to be received in bore 123 and bore section 125. Insert member 119 terminates with a lower end surface 119g at bore section 136 of sealing means 118. The outer surface of insert member 119 continues the continuity of 9 the seal forming surface 124. sealing means 118.

Insert member 119 has first, second and third bore portions, respectively, having increasing diameters from its outer surface, the first and third portions having grooves to receive O-rings 144, 151 while the second portion is threaded at 141 to receive a tubular stop tube 140 having a bore 142.

A thin walled cap 143 is sized to be received in the first bore portion of insert member 119. The outer surface 145 of cap 143 and O-ring 144 provides a fluid tight seal for the opening in the insert member 119. The end of stop tube 140 bears against the end of cap member 143. Fluid pressure in the well bore will retain the cap in position. If desired, cap 143 can be provided With a flange to seat on the shoulder between the first and second portions. Stop tube 140` may be conveniently screwed into insert member 119 by use of conveniently provided Wrench holes 174. Stop tube 140 is shouldered to abut the shoulder formed between the second and third bore portions of the insert member and the outer surface of stop tube 141) and O-ring 151 provide a uid tight seal.

The resilient means 118 and stop tube 140 are independently connected to a rigid compression member or front plate 128. Compression member 128 has a rearward threaded part 131 for threaded connection at 166 to housing means 165 and a flange portion 131 sealed by an O-ring 173 relative to the housing means 165. A central bore in the compression member 128 slidably receives the stop tube 148 and an O-ring 158 provides a fluid tight seal therebetween. A counterbore in the compression member 128 forms an abutment 147 which cooperates with a flange 146 on the stop tube 140 to limit outward travel of the stop tube 148 relative to the compression member 128. Inward travel of the stop tube 140 relative to the compression member 128 is limited by abutment of the end surface 119a of insert 119 with an abutment surface 125m on the compression member 128. From the foregoing, it will be appreciated that insert 119 and the functionally integral stop tube 140 may be moved relative to the compression memberV 128 and such movement will correspondingly move central portions of the resilient sealing means 118 therewith.

About the periphery of the compression member is a flange 129 .provided so that peripheral lip portions 130 on the resilient sealing -means 118 may be releasably connected to the compression member. Lip portions 130 need not be continuous but can be segmented and can be further confined between the flange 129 and a portion of housing means 165 where the compression member 128 is received in a shaped recess of the housing means 165.

etween the rearward surface 120a of the resilient means 118 and a forward surface of the compression member 128 is an annular rigid plate member 138. The plate member 138 overlies a fiuid communication means comprising one or more circular channels 132-134 which are interconnected for fluid communication by radial channels 13561. One or more channels or openings 135 are provided in the resilient means 118 in fluid communication with circular or spiral bore-fiuid-channeling recesses or channels 132-134. Channels 132-134 are also in fluid communication with the annular recess 136 in the resilient means 118 by virtue of the central opening 137 in the plate member 138.

Housing 165 has a chamber receiving a shaped charge 160. Charge 161B is inserted through a rearward opening of housing 165 and has a forward portion 167 adapted to engage a seat 168 on the compression member 128. The rearward end of the charge 161B is supported by a spring 169 seated in the chamber. A rear plug 170 is secured by threads 171 to the housing and sealed relatively thereto by an O-ring 172. Wrench openings 173 are provided in the plug 170 for assembly purposes.

Insert 119 is bonded t0 The sampling conduit 65 of the housing 165 is fluidly connected by ports 65a to the chamber in the housing.

If two of the foregoing devices described relative to FIG. 3 are used or substituted as the sample admitting means 21 and 22 of FIGS. l and 2, the operation is as follows:

In operation, sealing means 118 is initially compressed between the borehole wall and compression member 128. This is accomplished by apparatus heretofore described relative to FIGS. 1 and 2. The annular compression of the sealing means 118 will force the insert member 119 inwardly until the end surface 119a of insert 119 abuts surface 128a of the compression member. At the Same time, the annular recess 136 permits good compression of the sealing means 118 by providing a space for the elastomer to flow. Recess 136 is made large enough that the fiuid communication path through the central opening of plate 138 is not closed. In this way, a good compressive seal is obtained.

The shaped charge 160 in the housing means 165 is then detonated and provides a perforating jet in a wellknown manner. With initially atmospheric pressure within stop tube 141), the perforating jet builds up gas pressure rapidly while forming a perforating jet to penetrate the cap 143 and opens a passage 122 (see FIG. l1) in the lower pressure earth formations 13. The gas pressure provides an initial force urging the insert into contact with the formations. At this time, the hydrostatic pressure of fluid in the well bore has access via the communication means to the recess 136 and provides, independently of the compressive sealing force, a force urging insert 119 outwardly. As FIG. 1l shows, if the formation erodes with fluid flow, the insert 119 and attached central portion of the sealing means 118 will be main tained against the earth formations. At the same time, the hydraulic system to the tool which maintains the com-pression seal will continue to maintain the sealing means in compression. In short, the inner and outer circumferential portions of the sealing surface 124 of the sealing means 118 are independently, hydraulically maintained in sealing contact with the formation.

The circumferential outer surface of insert 119 is made large enough to bridge the formation perforation opening, thus preventing flow of the sealing element into the perforation opening.

After considerable erosion, the housing 165 may contact the borehole wall. lf the plate 138 is bonded to the sealing means, the pressure behind the plate 138 will strip the lips from ange 129 and hydrostatic pressure will maintain the sealing means 118 on the formations until the limit of travel of stop tube 148 is reached. Thereafter, continued erosion will eventually break the seal. However, by the time this occurs, a representative sample of formation fluids is obtained.

One of the significant features of this invention is the fact that a small sealing means can be used to obtain a fiuid sample with greater success because the sealing means of the present invention inhibits erosion. For example, if there is no travel of the center section of the sealing means, erosion spreads radially from the perforation since there is no direct force on the formation. This erosion can quickly remove the earth formations supporting a direct compressive seal and result in a poor or inconclusive fluid sample recovery.

The embodiment of FIG. 4 is similar to that of FIG. 3. However, in the embodiment of FIG. 4, stop tube 148 has a closure or cap means 176 sealing the rearward end of a passage 142. A cap means 177, `with the aid of an O-ring 178, is used to isolate the shaped charge 168 from fiow passages 65a. Thus, before detonation of the shaped charge, fiuid can be present: `in the passage 65a. This embodiment finds use in combination with a snorkel type sample admitting means 22 as shown in FIG. 2. The shaped charge is adapted to pierce, upon detonation, all three cap ymeans 177, 176, 143. The

cap means 176, 177 enable the passage 65a to contain Huid without having fluid in passage 142 or in the charge chamber. Thus, passage 142 can be maintained before firing of the shaped charge 160 at atmospheric pressure (or below, if desired) permitting use of a thinner wall in sleeve 140. Without cap means 143, 176, the wall of the sleeve must be great enough to avoid swelling when the perforating jet passes therethrough. If swelling occurs, of course, tube 149 would not be able to travel.

The embodiment of FIG. is similar to that of FIG. 3 but is a combination tube follower and shaped charge in one chamber and includes only one cap portion 177 to maintain the charge 160 dry. No cap portion corresponding to the cap porti-ons 143, 176 are used and tube 140a is made thicker to prevent swelling. The passages 65, 65a, 142 are thus in free communication even before firing of the shaped charge 160. This embodiment may be used in combination with the embodiment of FIG 4.

The embodiment of FIG. 6 differs from those of the preceding figures in that it is provided with a tube follower 61) (see also FIG. 2) having a bore 191 communieating via apertures 74 with a cylindrical cavity 64 which, in turn, communicates with the passages 65, 65a.

A piston 63 sealed by O-rings 196, retained in annular recesses 197, seals the piston 63 to the wall of the cylinder 64. The piston 63 has a forwardly extending portion 199 in 'which the apertures 74- may be located. The portion 199 is connected to the tube follower 60 by threads 206.

After compressing the sealing means 118 against the borehole wall, ioperating fiuid from the hydraulic system of the tool, which is provided access to the chamber 71, forces the piston 63 and the tube 60 outwardly and onto the earth formations. Any fluid present in the formation is then free to drain through the bore 191 of the tube follower 60, the apertures 74 in the extension 199, the cylinder 64, and the passages 65, 65a (see also FIG. 2).

The tube follower 6i) is integral with the insert 119, so the action produced by an influx of bore fluid in the recess 136 and that produced by an influx of operating fluid in the chamber 71 act in the same manner insofar as both move the insert 119 with respect to the compression member 128. However, the hydraulic operation fluid is advantageously used when the difference between formation fluid pressure and the hydrostatic pressure in the well bore is not too great. A tight seal between the seal forming surface and the wall of the bore is thus assured.

When the valve 40 is actuated (FIGS. 1 and 2), mud pressure facilitates retraction of tube 60. By making the tube of frangible material, the tube can be broken off should the tube fail to retract. Breaking of the tube 140 in the embodiment of FIG. 3 and other embodiments employing7 shaped charges is generally not possible because of the heavier construction of such tubes.

FIG. 7 shows an embodiment 4where a shaped charge is not employed. The tube follower 2114 is provided with a coil spring 205 -in compression between an outwardly extending circular fiange 266 at the rearward end of the tube follower 204 and an abutment 207 formed inwardly of the compression member 128. Formation fluid is allowed to iiow through a bore 209, a cavity 211i and passages 65a, 65. The resilient annular sea-ling means 118 is adapted to provide a seal and follow outwardly the wall of a crumbling formation or bore in the manner previously described. The annular sealing means, being resilient, is adapted to restore itself to its rest position after the taking of a sample and the equalization of pressure across the sealing means. In the embodiment of FIG. 7, however, the restoration of the resilient annular sealing means to its original shape is facilitated by the action of the compressed coil spring 205, which, upon expanding, moves the rigid means 119 rearwardly along the axis of the resilient annular sealing means 118 to restore the resilient annular sealing means 11% to its original condition.

The embodiment of FIG. 8 is similar to the embodiment of FIG. 6, the chief difference being that the embodiment of FIG. 8 includes a hydraulic snorkel follower rather than a hydraulic tube follower. The snorkel 212 is not functionally integral with the insert 119 or follower tube e. Hence, snorkel 212 can be forced through the sealing means 118 into the formation independently of the sealing means 118. O-rings 212', 212a, 212b maintain a fiuid tight seal between the snorkel 212 and the compression member 128, the snorkel and follower tube 141m and the follower tube 140g and insert 119. The snorkel 212 is provided at its forward end with a tapered portion 213 facilitating penetration of formations. It Iwi-ll be appreciated that, in addition to the independent hydraulic action on sealing means 11S, the snorkel 212 is independently driven into the earth formations.

In the embodiment of FIG. 9 a piston 213 is slidably received in a cylinder 214 to which it is slidingly sealed yby an O-ring 215 retained in a peripheral recess 216 in the circumferential wall of the piston 213. Operating fluid is supplied to a -chamber 71 to the rear of the piston 213 by means of which the piston can be forced forwardly. A stop portion 217 on the piston 213 is adapted to engage an inwardly extending annular shoulder 218 formed on a generally cylindrical sleeve 219 to limit the forward motion of the piston 213.

Piston 213 has a forward extension 221B with a flange 221 disposed between an annular plate 222 similar to the plate 138 and a plate member 226. Flange 221 includes a channel defining iiuid communication means similar to the channel defining means 131 of FIG. 3.

The extension 220 connected to the piston 213 by threads 213 is movable within an annular recess in the sleeve portion 219 of the plate member 226. Extension 220 is slidable through a bore 231 in the compression member and sealed relative thereto by an O-ring 230.

Forward movement of the piston 213 and the extension 220, therefore, also moves the flange 221 and the plate 222 forwardly together with the resilient annular sealing means 113, the insert 119 and a tube 231rz. Tube 231e is slidably and sealingly received Within a bore 220a of extension 220 so that insert 119 can move relative to fiange 221 and permit the resilient sealing means 118 to be held tightly in sealing engagement with the wall of a bore. The channel defining fluid communication means includes circular channels 233, 234, 235 and a radial channel 236, respectively, similar to the channels 132, 133, 134, and the channel 135 permits the additional movement of the insert 119 and the resilient annular sealing means 118 as described in connection with FIG. 3, so that the resilient sealing means is adapted to follow an eroding well bore wall. The plate member 226 is provided with an annular recess 223:1 which is in fluid communication via ports 223b with the fluid communication means channels, thus insuring access of the borehole fluids between members 222 and 226 and prevents hydraulic locking.

A significant feature of the embodiment of FIG. 9 is that the sealing means is movable as a unit away from the housing 165, thus obtaining seals in washed out or irregular wall surfaces in a well bore.

The embodiment of FIG. 10 is similar to the embodiment of FIG. 8. In particular, however, the piston 212a of snorkel tube 212 is open to the exterior of the tool permitting hydrostatic pressure to operate it rather than operating fluid as used in the embodiment of FIG. 8. This is accomplished by a plate member 212b attached to the housing providing uid access openings. Between plate 21211 and piston 212:1 is a frangible tubular member 212e, the purpose of which will hereinafter be made apparent.

Compression member 238 is provided with a plurality of radial channels and overlying the channels 239 is a plate member 240 which is bonded to the sealing means 118. Sealing means 118 is attached to an annular insert ring 241 slidably and sealingly received over tube 212. Tube 212 is, of course, sealed relative to the bore in the compression member 238 by an O-ring 242. Sealing means 118 has a recess 243 provided in the forward connection between insert 241 and tube 212 to accommodate expansion of the sealing means 118 upon compression. Insert 241 also has an internal annular recess 244 extending about the tube 212.

In operation, if erosion of formations occurs, a void space is created which insert 243 tends to fill and, once moved, hydrostatic pressure acts on the insert 243 as described heretofore. It will be appreciated that the positioning of the recess 243 forward of the sealing means can be accomplished but is not as advantageous as a rearward recess. The frangible disc 212C serves to insure that, in hard formations, the tube 212 is not crushed. That is, upon compression of the sealing means 118 and contact of tube 212 with the borehole wall, the disc can be crushed to prevent overload on the tube 212.

The plate members used in supporting the resilient means and providing the fluid communication means may be bonded to the sealing means or loose. The difference is that, with a bonded attachment, the plate is sure to operate and maintain a compression seal after the compression member is no longer available.

The fluid communication path between the compression member and supporting plate members is made of annular recesses to reduce the bearing surface area between the compression and plate members so as to avoid hydraulic locking of the members to one another yet provide strong supporting structure over the entire plate member.

Thus, there is provided in accordance with the invention novel and highly effective formation testing apparatus and methods directed to the acquisition of a tiuid sample from earth formations traversed by a bore. Inasmuch as numerous modifications within the spirit and scope of the invention will occur to workmen having the ordinary skill of the art, the invention is to be construed as including all of the modifications thereof which fall within the scope of the appended claims.

We claim:

1. An article for use in a well bore comprising resilient annular sealing means for establishing a pressure seal on the wall of a well bore, said resilient annular sealing means having an outer periphery for communication with the well bore, an inner periphery, a forward seal forming surface between said outer periphery and said inner periphery, and a rearward surface, tubular, rigid insert means shaped complementarily to and connected to said inner periphery with an outer surface complementary to said seal forming surface and large enough to cover a perforation in earth formations for preventing extrusion of said resilient annular sealing means into said perforation, said tubular rigid insert means having first, second and third sections with progressively increasing internal diameters from the outer surface, said first and one of said second and third sections being grooved to receive O-rings and the remaining of said second and third sections being threaded.

2. An article for use in a well bore comprising resilient annular sealing means for establishing a pressure seal on the wall of a well bore, said resilient annular sealing means having outer circumferential port-ions and a central portion, rigid compression means with outer circumferential portions for applying pressure to the outer eir- 4cumferential portions of said sealing means when such sealing means contacts the wall of a well bore, rigid insert means connected to the central portion of said sealing means with a forward portion adapted for Contact with the wall of a well bore and a rearward portion arranged for receiving pressure, said insert means having means defining a iiuid communication path, said compression means including means for accommodating passage of said fluid communication path therethrough, and channel means between said compression means and sealing means and extending across said compression means from said outer circumferential portions of said compressions means to said central portion of said resilient annular sealing means for placing said rearward portion of said insert means in uid communication with a source of iuid pressure for independent response to such liuid pressure.

3. An article as defined in claim 2 and further where said uid communication means includes a tube member and said passage accommodating means includes a bore.

4. An article as defined in claim 3 and further where said tube means and compression means have stop means for limiting the movement of said tube with respect to said compression means. Y

5. An article for use in a well bore comprising resilient annular sealing means for establishing a fluid tight seal on the wall of a well bore between the pressure of fluids in a well bore and the pressure of iluids in earth formations, said resilient annular sealing means having an outer periphery for communication with fluid in a well bore, an inner periphery, a forward seal forming surface between said outer periphery and said inner periphery, and a rearward surface, rigid insert means connected to said inner periphery, rigid compression means having circumferential portions for applying a circumferential pressure to said sealing means when said sealing means are compressed between said compression means and the wall of a well bore, said insert means including a depending tube, said compression means having a bore slidably and sealingly receiving said tube, and means for independent Iapplication of pressure to said insert means between said compression means and insert means for independent movement of said insert means relative to said compression means.

6. Apparatus for forming and maintaining a fluid tight seal with the wall of a fiuid filled well bore comprising resilient annular sealing means for establishing an annular iiuid tight seal on the wall, said resilient annular s-ealing means having an outer periphery for communication with the well bore, an inner periphery, a seal forming surface between said outer periphery and said inner periphery arranged for contact with the well bore wall, and a rear surface between said outer periphery and said inner periphery, and opposite said seal-forming surface, rigid insert means connected to said inner periphery, rigid compression means with outer circumferential portions for circumferentially applying pressure .to said resilient annular sealing means adjacent to said outer periphery, and channel means between said compression means and sealing means and extending across said compression means from said outer circumferential portions of said compression means to a point adjacent to said inner per-iphery of said resilient annular sealing means for admitting fluid from said bore into contact with said insert means at least adjacent to said inner periphery to force said rigid insert means against said wall independently of said compression means.

7. Apparatus for forming and maintaining a pressure tight seal with the wall of a fiuid lill-ed well bore comprising annular elastomer seal-ing means for establishing an annular pressure seal on the wall, said sealing means having a central bore and surrounding circumferential portions arranged for compression, said circumferential portions having a forward sealing surface and a rearward compression surface, insert means attached to said sealing means in said central bore, rigid compression means having circumferential portions substantially coextenisve with said rearward compression surface for applying pressure to said sealing means when it engages the wall of a well bore, said compression means having a central bore, said insert means having a tubular extension slidably and sealingly received in said central bore of said compression means, said insert means and circumferential portions of said sealing means having a pressure recess therebetween, said circumferential porltions of said compression means having bore-fluid channeling recesses 4in communication with one another, a

plate member disposed between said rearward compression surface and said circumferential portions of said compression means so as to overlie said bore-fluid channeling recesses, said plate member having an access opening to said pressure recess, said bore-fluid channeling recesses having an access opening to the exterior of the apparatus for receiving well bore fluid.

8. Apparatus for forming and maintaining a pressure tight seal with the wall of a fluid filled well bore comprising annular elastomer sealing means for establishing an annular pressure seal on the wall, said sealing means having a central bore and surrounding circumferential portions arranged for compression, said circumferential portions having a forward sealing surface and a rearward compression surface, tubular, rigid insert means attached to said sealing means in said central bore, cap means sealingly received in said insert means, compression means having circumferential portions substantially coextensive with said lrearward compression surface for applying pressure to said sealing means when it engages the wall of a well bore, said compression means having a central bore, said insert means having a tubular extension slidably and sealingly received in said central bore of said compression means, said insert -means and circumferential portions of said sealing means having a pressure recess therebetween, said circumferential portions of said compression means having a bore-uid channeling recess, a plate member disposed between said rearward compression surface and said circumferential portions of said compression means so as to overlie said bore-fluid channeling recess, said plate member having an access opening to said pressure recess, said bore-Huid channeling recess having an access opening to the exterior of the apparatus for receiving well bore iiuid.

9. Apparatus for testing well formations including a housing, annular elastomer sealing means for establishing an annular pressure seal on the wall, said sealing means having a central bore and surrounding circumferential portions arranged for compression, said circumferential portions having a forward sealing surface and a rearward compression surface, tubular, rigid insert means -attached to said sea-ling means in said central bore, cap means received in said insert means, compression means having circumferential portions substantially coextensive with said rearward compression surface for applying pressure to said sealing means when it engages the wall of a well bore, said compression means being connected to said housing, said compression means having a central bore, -said insert means having a tubular extension slidably and sealingly received in said central bore of said compression means, said insert means and circumferential portions of said sealing means having a pressure recess therebetween, said circumferential portions of said compression means having bore-fluid channeling recesses in communication with one another, a plate member disposed between said rearward compression surface and said circumferential portions of said compression means so as to overlie said bore-fluid channeling recesses, said plate member having an access opening to said pressure recess, said bore-iiuid channeling recesses having an access opening to the exterior of the apparatus for receiving well bore fluid, perforating means in said housing aligned with said tubular extension.

1t). Apparatus for testing well formations including a housing annular elastomer sealing means for establishing an annular pressure seal on the wall, said sealing means having a central bore and surrounding circumferential portions arranged for compression, said circumferential portions having a forward sealing surface and a rearward compression surface, tubular, rigid insert means attached to said sealing means in said central bore, compression means having circumferential portions substantially coextensive with said rear,vi/,arri compression surface for applying pressure to said sealing means when it engages the wall of a well bore, said compression means being connected to said housing, said compression means having a central bore, said insert means having a tubular extension slidably and sealingly received in said central bore of said compression means, cap means sealingly received in the forward and rearward portions of said tubular extension, said insert means and circumferential portions of said sealing -means having a pressure recess therebetween, said circumferential portions of said compression means having bore-fluid channeling recesses in communication with one another, a plate member disposed between said rearward compression surface and said circumferential portions of said compression means so as to overlie said borefluid channeling recesses, said plate member having an access opening to said pressure recess, said bore-fluid channeling recesses having an access opening to the exterior of the apparatus for receiving well bore uid, perforating means in said housing alinged with said tubular extension. p

1l. Apparatus for testing well formations including a housing, annular elastomer sealing means for establishing an annular pressure seal on the wall, said sealing means having a central bore and surrounding circumferential portions arranged for compression, said circumferential portions having a forward sealing surface and a rearward compression surface, tubular, rigid insert means attached to said sealing means in said cental bore, compression means having circumferential portions substantially coextensive with said rearward compression surface for applying pressure to said sealing means when it engages the wall of a well bore, said compression means being connected to said housing, said compression means having a central bore, said insert means having a tubular extension slidably and sealingly received in said central bore of said compression means, said insert means and circumferential portions of said sealing means having a pressure recess therebetween, said circumferential portions of said compression means having bore-fluid channeling recesses in communication with one another, a plate member disposed between said rearward compression surface and said circumferential portions of said compression means so as to overlie said bore-fluid channeling recesses, said plate member having an access `opening to said pressure recess, said bore-fluid channeling recesses having an access opening to the exterior of the apparatus for receiving well bore iiuid, said housing having a chamber, perforating means in said chamber aligned with said tubular extension, cap means sealingly received in the forward and rearward portions of said tubular extension, and cap means sealingly closing said chamber.

12. Apparatus for testing well formations including a housing, annular elastomer sealing means for establishing an annular pressure seal on the wall, said sealing means having a central bore and surrounding circumferential portions having a forward sealing surface and a rearward compression surface, tubular, rigid insert means attached to said sealing means in said central bore, compression means having circumferential portions substantially coextensive with said rearward compression surface for applying pressure to said sealing means when it engages the Wall of a well bore, said compression means being connected to said housing, said compression means having a central bore, said insert means having a tubular extension slidably and sealingly received in said central bone of said compression means, said insert means and circumferential portions of said sealing means having a pressure recess therebetween, said circumferential portions of said compression means having bore-fluid channeling recesses in communication with one another, a plate member disposed between said rearward compression surface and said circumferential portions of said compression means so as to overlie said bore-Huid channeling recesses, said plate member having an access opening to said pressure recess, said bore-fluid channeling I7 recesses having an access opening to the exterior of the apparatus for receiving well bore uid, said housing having a chamber, perforating means in said chamber aligned with said tubular extension, and cap means for sealingly closing said chamber.

13. Apparatus for testing well formations including a housing, annular elastomer sealing means for establishing an annular pressure seal on the wall, said sealing means having a central bore and surrounding circumferential portions ar-ranged for compression, said circumferential portions having a forward sealing surface and a rearward compression surface, insert means attached to said sealing means in said central bore, rigid compression means having rst and second cylinder bores and having circumferential portions substantially coextensive with said rearward compression surface for applying pressure to said sealing means when it engages the wall of a well bore, said compression means being connected to said housing, said insert means having a tubular extension slidably and sealingly received in said first cylinder bore of said compression means, said insert means and circumferential portions of said sealing means having a pressure recess therebetween, said circumferential portions of said compression means having bore-fluid channeling recesses in communication with one another, a plate member disposed between said rearward compression surface and said circumferential portions of said compression means so as to overlie said bore-fluid channeling recesses, said plate member having an 'access opening to said pressure recess, said bore-huid channeling recesses having an access opening to the exterior of the apparatus for receiving well bore iluid, said tubular extension having a piston member received in said second cylinder bore so that pressure may be applied to said piston member.

14. Apparatus for testing well formations including a housing, annular elastomer sealing means for establishing an annular pressure seal on the wall, said sealing means having a central bore and surrounding circumferential portions arranged for compression, said circumferential portions having a forward sealing surface and a rearward compression surface, tubular insert means attached to said sealing means in said central bore, lrigid compression means having rst and second cylinder bores and having circumferential portions substantially coextensive with said rearward compression surface for applying pressure to said sealing means when it engages the wall of a well bore, said compression means being connected to said housing, a tubular member slidably and sealingly received in said insert means and said rst cylinder bore of said compression means, said insert means and circumferential portions of said sealing means having a pressure recess therebetween, said circumferential porti-ons of said compression means having bore-fluid channeling recesses in communication with one another, a plate member disposed between said rearward compression surface and said circumferential portions of said compression means so as to overlie said bore-fluid channeling recesses, said plate member having an access opening to said pressure recess, said bore-duid channeling recesses having an access opening to the exterior of the apparatus for receiving well bore fluid, said tubular member having a piston member received in said second cylinder bore so that pressure may be applied to said piston member.

15. Apparatus for testing well formations including a housing, annular elastomer sealing means for establishing an annular pressure seal on the wall, said sealing means having a central bore and surrounding circumferential portions arranged for compression, said circumferential portions having a forward sealing surface and a rearward compression surface, tubular insert means attached to said sealing means in said central bore, rigid compression means having circumferential portions substantially coextensive with said rearward compression surface for applying pressure to said sealing means when it engages the wall of a well bore, said compression means having a central bore, said insert means having a tubular extension slidably and sealingly received in said central bore of said compression means, said insert means and circumferential portions -of said sealing means having a pressure Irecess therebetween, said circumferential portions of said compression means having bore-fluid channeling recesses in communication with `one another, a plate member disposed between said rearward compression surface and said circumferential portions of said compression means so as to overlie said bore-iiuid channeling recesses, said plate member having an access opening to said pressure recess, said bore-fluid channeling recesses having :an access opening to the exterior of the apparatus for receiving well bore fluid, said housing having a cylinder bore, said compression means having an extension with a piston member received in said cylinder bore so that pressure may be applied -to said piston member.

15. Apparatus for testing well formations including a housing, annular elastomer sealing means for establishing an annular pressure seal on the wall, said sealing means having a central bore and surrounding circumferential portions arranged for compression, said circumferential portions having a forward sealing surface and a rearward compression surface, tubular insert means attached to said sealing means in said central bore, rigid compression means having a cylinder bore and having circumferential portions substantially coextensive with said rearward compression surface for applying pressure to said sealing means when it engages the wall of a well bore, said insert means having .a tubular extension slidably and sealingly received in said cylinder bore of said compression means, said insert means and circumferential por-Y tions of said sealing means having a pressure recess therebetween, said circumferential portions of said compression means having bore-fluid channeling recesses in communication with one another, a plate member disposed between said rearward compression surface and said circumferential portions of said compression means so as to overlie said bore-Huid channeling recesses, said plate member having an access opening to said pressure recess, said bore-fluid channeling recesses having an access opening to the exterior of the apparatus for receiving well bore fluid, backing means mounted in said housing substantially coextensive with said compression means and having rst and second center bores, said compression means having an extension member slidably and sealingly received in said first center bore and a piston member received in said second center bore so that pressure may be applied to said piston member.

17. The apparatus of claim 7 and further including resilient means disposed between said compression means and tubular extension tending to urge said extension inwardly into said compression means.

18. Apparatus for testing well formations including a housing, annular sealing means for establishing an annular pressure seal on the wall, said sealing means having a central bore and surrounding circumferential portions arranged for compression, said circumferential portions having a forward sealing surface and a rearward compression surface, tubular insert means attached to said sealing means in said central bore, rigid compression means having circumferential portions substantially coextensive with said rearward compression surface for applying pressure to said sealing means when it engages the wall of a well bore, said compression means being connected to said housing, said -compression means having a central bore, a tubular member slidably and sealingly received in said insert means and said central bore of said compression means, said circumferential portions of said compression means having fluid access means from the exterior of said compression means to said insert means, a plate member disposed between said rearward compression surface and said circumferential portions of said compression means so as to overlie said fluid access means, said plate member having an access opening to said pressure recess, said housing having a cylinder bore, said tubular member having a piston member reecived in said cylinder bore.

19. In combination with a uid testing tool including a body adapted to be lowered through a well bore extending through earth formations, spaced sample admitting means on said body adapted to be urged into engagement with a well bore, said sample admitting means each including resilient annular sealing means for establishing a fluid seal on the wall of the well bore and at least one of said sample admitting means including insert means and compression means for circumferentially acting on said sealing means, said insert means being attached centrally of said sealing means and having an aperture slidably and sealingly receiving a fluid tube sampling means mounted in said body for transverse movement into earth formations when said sample admitting means are in sealing engagement with a well bore, means for placing the portion of said insert means adjacent said compression means in Huid communication with the well bore to urge said insert means against the wall of said well bore, means for hydraulically actuating said sampling means, the other of said sample admitting means being normally closed to fluid flow from the well bore and within the body and including selectively operable perforating means for selectively opening said other sample admitting means.

20. In combination with a fluid testing tool including a body adapted to be lowered through a well bore extending through earth formations, spaced sample admitting means on said body adapted to be urged into engagement with a well bore, said sample admitting means each including resilient annular sealing means for establishing a fluid seal on the wall of the well bore and at least one of said sample admitting means including insert means and compression means for circumferentially acting on said sealing means, said insert means attached centrally of said sealing means and having an aperture slidably and sealingly receiving a liuid tube sampling means mounted in said body for transverse movement into earth formations when said sample admitting means are in sealing engagement with a well bore, means for placing the portion of said insert means adjacent said compression means in fluid communication with the well bore to urge said insert means against the wall of said well bore, means for hydraulically actuating said sampling means, the other of said sample admitting means including selectively operable perforating means for selectively opening said other sample admitting means, and means for normally isolating said perforating means from fluids.

21. A fluid testing tool comprising a body adapted to be lowered through a well bore extending through earth formations, spaced sample admitting means on said body including resilient annular Sealing means for establishing a uid seal on the wall of a well bore, said resilient annular sealing means having an outer periphery, insert means centrally connected to said resilient annular sealing means, and compression means for circumferentially applying pressure to said resilient annular sealing means, said insert means being movable with respect to said compression means, means coupled to said body to urge said resilient annular sealing means into sealing engagement with a well bore, a fluid sampling tube mounted in said body centrally of one of said sealing means for transverse movement into earth formations, means in said body for moving said uid sampling tube into earth formations, a sample receiving chamber in said body, means providing a fluid conduit between said sampling tube and said sarnple receiving chamber, and means for selectively providing a fluid connection between the other sealing means and said fluid conduit means including a fiow blocking device normally closing olf said other sealing means from the well bore and perforating means in said body disposed centrally of the said other sealing means, said perforating means, upon tiring, serving to open said other sealing means and penetrate the earth formations.

22. A fluid testing tool comprising a body adapted to be lowered through a well bore extending through earth formations and containing a uid, longitudinally spaced sample admitting means yon said body including resilient annular sealing means -for establishing a pressure seal on the wall of the well bore, said resilient annular sealing means having an outer periphery for communication with well bore uids, an inner periphery, and a seal forming surface between said outer periphery and said inner periphery, insert means connected to said inner periphery, compression means for applying pressure to said sealing means, and means facilitating movement of said rst insert means with respect to said compression means along the axis of the resilient annular sealing means, means on said body to urge said sealing members into sealing engagement with a well bore, a uid sampling tube having a piston mounted in a cylinder in said body centrally of one of said sealing members for transverse movement into earth formations, hydraulic means in said body operable on said piston for moving said uid sampling tube into earth formations, a sample receiving chamber in said body, means providing a fluid conduit between said sampling tube and said `sample receiving chamber, means for selectively providing a Huid connection between the sealing member and said iluid conduit means including a tiow blocking device normally closing off said sealing member fro-m the well bore, and shaped charge means in said body disposed centrally of said Iother sealing member, said shaped charge means, upon detonation, serving to open said ow blocking device and penetrate the earth formations.

23. The apparatus of claim 22 wherein said means to urge said sealing means into scaling engagement with a well bore include hydraulic actuating means, means coupling said hydraulic means to said hydraulic actuating means including a time delay device to permit said sealing means to be placed in sealing engagement with a well bore before said hydraulic means are operable.

24. In combination with a fluid testing tool including a body adapted to be lowered through a well bore extending through earth formations, spaced sample admitting means on said body adapted to be urged into engagement with a well bore, said sample admitting means each including resilient annular sealing means for establishing a pressure seal `on the wall of the well bore and at least one of said sample admitting means including insert means and compression means for circumferentially acting on said sealing means, said insert means being attached centrally of said sealing means and there being a portion of said insert means adjacent said compression means, and fluid communication means between said compression means and sealing means for placing the portion of said insert means adjacent said compression means in uid communication with the well bore, means permitting hydraulic actuation of said compression means for movement relative to said body.

25. In combination with a fluid testing tool including a body adapted to be lowered through a well bore extending through earth formations, spaced sample admitting means on said body adapted to be urged into engagement with a well bore, said sample admitting means each including resilient annular sealing means for establishing a pressure seal on the wall of the well bore and each of said sample admitting means including insert means and cornpression means for circumferentially acting on said sealing means, said insert means being attached centrally of said sealing means and there being a portion of said insert means adjacent said compression means, and uid communication means between said compression means and sealing means for placing the portion of said insert means adjacent said compression means in fluid communication with the well bore, means permitting hydraulic actuation of said compression means for movement relative to said body.

26. Apparatus for forming and maintaining a fluid seal between a high pressure region and a low pressure region both in communication with a material tending to dissociate with fluid flow comprising resilient annular sealing means having an outer resilient periphery adapted to be placed in communication with said high pressure region, an inner rigid periphery adapted to be placed adjacent t said low pressure region, and a seal-forming surface between said outer resilient periphery and said inner periph ery, means for positioning said resilient annular sealing means adjacent to said material to establish a fiuid seal between said high pressure region and said low pressure region, means including a tubular member aflixed to and independently movable with the inner rigid periphery for conducting fluid from said low pressure region to a collection chamber, means for thereafter conducting high pressure uid from said high pressure region to the inner periphery of said sealing means in closely-spaced relation to said sealing means, and means for employing said high pressure fluid to independently apply pressure on the portion of said seal-forming surface adjacent to said inner periphery, whereby said uid seal between said high pressure region and said low pressure region is maintained and tubular member is urged toward the low pressure region to maintain fluid flow from the low pressure region to the collection chamber through the tubular member as the material disassociates under the infiuence of iluid ilow.

27. Apparatus for use in a well bore comprising resilient sealing means having an outer resilient portion and a rigid central portion including a tubular member in iixed relation to the adjacent portion of the resilient sealing means and independently movable therewith for conducting fluid from one side of the sealing means to the opposite side thereof, each of said portions having forward and rearward surfaces, means for positioning said resilient sealing means against the wall of a well bore, means for applying a lateral force outwardly against said rearward surface of said outer portion to establish an annular fluid seal on the wall of a well bore with said forward surfaces of said -outer portion, and means for thereafter conducting fluid from the well bore exterior of said outer portion to said rearward surface of said central portion to independently apply pressure thereon for urging said forward surface of said central portion including the tubular member outwardly in advance of said forward surfaces of said outer portion so as to maintain a fluid seal with the wall as it erodes in front of .said central portion, and maintain iiuid communication between the two sides of the sealing means through the tubular member.

References Cited by the Examiner UNITED STATES PATENTS 2,582,719 1/1952 Ramsey 166-100 X 2,612,346 9/1952 Nelson 166-l00 X 2,821,256 1/1958 Boller 166-100 2,905,247 9/1959 Vestermark 166-100 2,965,176 12/1960 Brieger et al 166-10O 3,173,485 3/1965 Bretzke 16610O 3,217,804 11/1965 Peter 166--100 X CHARLES E. OCONNELL, Primary Examiner.

D. H. BROWN, Assistant Examiner. 

25. IN COMBINATION WITH A FLUID TESTING TOOL INCLUDING A BODY ADAPTED TO BE LOWERED THROUGH A WELL BORE EXTENDING THROUGH EARTH FORMATIONS, SPACED SAMPLE ADMITTING MEANS ON SAID BODY ADAPTED TO BE URGED INTO ENGAGEMENT WITH A WELL BORE, SAID SAMPLE ADMITTING MEANS EACH INCLUDING RESILIENT ANNULAR SEALING MEANS FOR ESTABLISHING A PRESSURE SEAL ON THE WALL OF THE WELL BORE AND EACH OF SAID SAMPLE ADMITTING MEANS INCLUDING INSERT MEANS AND COMPRESSION MEANS FOR CIRCUMFERENTIALLY ACTING ON SAID SEALING MEANS, SAID INSERT MEANS BEING ATTACHED CENTRALLY OF SAID SEALING MEANS AND THERE BEING A PORTION OF SAID INSERT MEANS ADJACENT SAID COMPRESSION MEANS, AND FLUID COMMUNICATION MEANS BETWEEN SAID COMPRESSION MEANS AND SEALING MEANS FOR PLACING THE PORTION OF SAID INSERT MEANS ADJACENT SAID COMPRESSION MEANS IN FLUID COMMUNICATION WITH THE WELL BORE, MEANS PERMITTING COMMUNICATION OF SAID COMPRESSION MEANS FOR MOVEMENT RELATIVE TO SAID BODY. 